That design on the mug! That's exactly how I picture the shirt I want in terms of size and spacing between iterations of the picture. I think the butterfly might work for that too, but I like it a lot in that frame. I'd hang that, no doubt.

Also, I hadn't seen the Smurfentaart design. That definitely belongs on a T-Shirt, it's fitting! I hope you find much success on Redbubble.